1 SRF (priyankakumari1983@gmail.com); 2 Senior Scientist (rajeev_micro@iari.res.in), Division of microbiology; 3 Ph D student (binutripathi@snu.ac.kr), School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, Republic of Korea, 151742; 4 R A (singhcsjm@gmail.com); Microbial Genomics Lab, National Bureau of Agriculturally Important Microorganisms, Mau Nath Bhanjan, Mau, Uttar Pradesh 275 101, 5 Head (saxena461@yahoo.com) Discharge of pulp and paper mill include many environmental pollutants among which chlorophenols (CPs) are major ones (Chandra et al. 2009), which are generated as the by-products when chlorine is used for bleaching of pulp and as water disinfectant. Pentachlorophenol (PCP) and its sodium salt have been widely used as wood and leather preservative owing to their toxic effect on bacteria, mould, algae and fungi (Kaoa et al. 2004). Its frequent and widespread use has led to contamination of aquatic and terrestrial ecosystems (Jensen 1996). Pulp paper industries are the sixth largest effluent generating industries of the world (Ugurlu et al. 2007). Since early fifties the number of paper pulp mills in India has increased from 17 to more than 406 in 2008, with simultaneous increase in paper production from 0.13 to 1.9 million tons per annum (Singh and Thakur 2006). Paper mill generates as low as 1.5 m 3 of effluent per ton to as high as 60 m 3 tonne of paper produced (Asghar et al. 2007). The safe permissible limit of PCP in water is 0.30 μg/l (US EPA 1999). However, in our country, the large units of pulp and paper mills discharge their effluent, having residual PCP in high concentrations (> 80 mg/l effluent), in local water ways (Raj et al. 2005). Pulp and paper mill effluent irrigation to crops is a cheap and attractive option compared to discharge of this effluent into natural waterways (Muthukumar and Vediyappan 2010). Local farmers irrigate their agricultural fields on regularly basis from these water channels and thereby contaminating them with PCP. Being highly chlorinated, PCP is expected to be recalcitrant to aerobic biodegradation as in general, aromatic compounds with higher amounts of chlorine are more resistant to biodegradation (Anandarajah et al. 2000). Due to persistence of PCP in soil and water environments, both the European and US Environment Protection Agencies have classified PCP as a ‘priority pollutant’ and have recommended restricted use to minimize its further accumulation and to circumvent toxicity of the ecosystem. Biological treatment of PCP attracts more attention than physical and chemical methods, because a variety of 124 Indian Journal of Agricultural Sciences 84 (1): 124–30, January 2014/Article https://doi.org/10.56093/ijas.v84i1.37168 Genetic and metabolic profiling of pentachlorophenol utilizing bacteria from agricultural soil irrigated with pulp and paper mill effluent PRIYANKA KUMARI 1 , RAJEEV KAUSHIK 2 , BINU M TRIPATHI 3 , RAM N SINGH 4 and ANIL K SAXENA 5 Indian Agricultural Research Institute, New Delhi, 110 012. Received: 24 August 2012; Revised accepted: 12 June 2013 ABSTRACT Pulp and paper mill is a source of major environmental pollutants generating industries which include pentachlorophenol a highly chlorinated aromatic compound. PCP degrading bacterial isolates obtained from pulp and paper mill effluent contaminated site were characterised using amplified ribosomal DNA restriction analysis of 16S rRNA gene. Based on cluster analysis the representative 13 isolates were identified by partial 16S rRNA gene sequencing. These PCP degrading bacterial isolates were classified into four major bacterial lineages, α, β, γ-Proteobacteria and Firmicutes. The PCP max and IC 50 values of these isolates ranged from 100 to 300 mg PCP/l and 125 to 375 mg PCP/l respectively. Pseudomonas aeruginosa (PCP1) and Pseudomonas sp (PCP42) exhibited maximum PCP max andIC 50 value. Degradation of PCP by these isolates at their respective PCP max ranged from 67.25% to 72.98% as analysed by the HPLC. Metabolic substrate usage of the isolates was evaluated using the BIOLOG TM ECO plates and unique carbon substrate usage profiles were observed. PCP degrading isolates, Azospirillum (PCP13 and PCP16) and Inquilinus limosus (PCP 27) were reported for the first time, these might represent new chlorophenol-degrading taxa. Key words : BIOLOG, Culturable diversity, Pentachlorophenol utilizing bacteria, Pulp and paper mill effluent